Putting It Together: Cell Division

Summary

In this competency you learned about these topics:

  • The two types of chromosomes found in humans (and many other sexually reproducing eukaryotes)
  • The chromosomal makeup of human body cells and gametes
  • The stages of mitosis, cell division in body cells
  • The various cell cycle checkpoints controlling normal cell division
  • The stage of meiosis, cell division that results in gametes
  • How to examine human chromosomal makeup using a karyotype and some gross impacts of incorrect chromosome numbers

Synthesis

Returning to our earlier look at cancer, let’s examine what often happens during treatment. Cancer therapies are designed to target actively dividing cells. Besides cancer cells, what other cells actively divide in humans? One of the most physically obvious side effects of cancer treatments is hair loss. This is because the living cells in the hair root continually divide to make hair grow longer. These cells therefore are often impacted by broad scale cancer treatments like chemotherapy drugs and radiation localized to the head. Shortly after cancer treatments, a patient’s blood count may also drop. This is due to the rapid division of blood cells throughout a person’s life. Unlike hair cells though, blood cells divide fairly often and rapidly. Hence, the blood count often returns to normal much faster than hair regrows.

As scientists learn more about cell division and the unique ways it malfunctions in cancer cells, they are able to develop targeted therapies. These drugs are still chemotherapies, but they are often focused on a particular feature of different types of cancer cells, making them less likely to target non-cancerous dividing cells. This reduces global side effects. Unfortunately, our understanding of cancer is still incomplete. Therefore, every day cancer researchers and clinicians work to manage and treat these horrible diseases.

Read more at www.cancer.org